1. Field of the Invention
The present invention relates to improvements in a position pointing device used for an apparatus for detecting a position indicated by the position pointing device utilizing electromagnetic induction.
2. Description of the Related Art
Conventionally, position pointing devices have been known which control characteristics of a resonant circuit provided therein in accordance with data of a switch or a writing pressure at timing synchronized with an electromagnetic wave intermittently transmitted from a tablet and which return the resulting information to the tablet. Examples include Patent Document 1 (Japanese Unexamined Patent Application Publication No. 3-189716), Patent Document 2 (Japanese Unexamined Patent Application Publication No. 7-175572), and Patent Document 3 (Japanese Unexamined Patent Application publication No. 7-200137).
Those position pointing devices can operate on only power that is transmitted from a tablet, i.e., can achieve battery-less configurations, by incorporating a low-power consumption digital circuit (i.e., a gate array) as a primary control circuit using a C-MOS technology. Yet, lower power consumption has been desired in order to allow a reliable operation even with lower power transmitted from the tablet.
The above-described position pointing devices have some problems. Specifically, the digital circuit (the gate array) for use as a control circuit needs to be customized according to applications. This makes it difficult to change the type of pointing-device information or the number of bits to be returned and also makes it impossible to provide a position pointing device that serve purposes. Additionally, cost for design is high.